The present invention relates to lamps used on motor vehicles, and more particularly to a lamp construction using light emitting diodes as the light source.
The term motor vehicle is used herein in a generic sense to mean automobiles, truck tractors, trailers of all types, motorcyles, and recreational vehicles such as boats, snowmobiles and the like, as well as aircraft. The above list is not all inclusive because new vehicles requiring lamps which move, or are moved on roads, waterways, and in the air will continually be developed.
Numerous problems exist with lamps presently used on motor vehicles. For example, present lamps, such as for example clearance and side marker lamps used on automobiles, truck tractors, and trailers, use standard high-intensity incandescent bulbs as a light source, and an optical lens over the bulb to provide a proper photometric light pattern. The lens also protects the bulb from damage from road debris and moisture. These high-intensity bulbs have a relatively short life and, therefore, must be frequently replaced. Further, in practice, it often happens that burned-out incandescent bulbs are not promptly replaced resulting in an unsafe vehicle condition.
Recent technology has developed light-emitting diodes which are a viable light source for various motor vehicle lamps such as side marker lamps and clearance lamps. An advantage of these light-emitting diodes is that they have an operating life of as much as 100,000 hours before they begin to degrade. However, a problem with the use of light-emitting diodes for motor vehicle lamps is that the position of the light-emitting diodes is very critical in order for the lamp to provide proper photometric criteria, for example, the photometric requirements of applicable United States Federal Motor Vehicle Safety Standards.